Washington has warned its ally Israel of potential embarrassment from the expected release of US diplomatic cables on whistle-blowing website WikiLeaks, an Israeli newspaper said on Thursday.

A senior Israeli official, quoted in Haaretz, said it has been informed that WikiLeaks plans to release hundreds of thousands of diplomatic cables, some of which could include confidential reports from the US embassy in Tel Aviv.

"The Americans said they view the leak very seriously," he told the paper, on condition of anonymity.

"They don't know when they will be released on the Internet and what exactly they say, but they didn't want us to read about it in the newspapers," the Israeli official said.

Embassy spokesman Kurt Hoyer, contacted by AFP, declined to comment except to say that such leaks could put lives at risk.